Grate bar



June 30, 1942.

- Filed Deo. A2, 1939 2 Sheets-Sheet'l f INVENTOR June 30, 1942. W LLOYD y' 2,288,006

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@Il umile', mmm... m MIIILH I n w IW j@ 11:? im -J ii .I l dgl: Imm., Sq 34H f il" f il f I mmf' i lmmv'f m I l g vu I N Patented June 3G, 1942 GRATE BAR William Lloyd, New York, N. Y., assigner to Combustion Engineering Company, lnc., New York,

Application December 2, 1939, Serial No. 307,220

3 Claims.

The present invention relates to travelling grate stokers and particularly to improvements in fuel supporting keys for use in such stokers.

An object of the invention is to provide an improved key designed to minimize the sifting of fuel through the air passages or slots between the sides of adjacent keys. Another object is to provide a key with sealing ribs so arranged as to improve the distribution of air to the fuel bed.

The invention will be best understood upon consideration of the following detailed description of an illustrative embodiment of the invention when read in conjunction with the accompanying drawings in which:

Figure 1 is a partial plan view of a travelling grate provided with fuel supporting keys embodying the present invention;

Figure 2 is a sectional View on the line 2 2 cf Fig. l;

Figure 3 is an enlarged plan view partly in sec tion of one of the fuel supporting keys.

Figure 4 is a side elevational view of one of the keys.

Figure 5 shows several of the keys in end view; and

Figure 6 is a section on the line 6 6 in Fig. 4.

In Figs. 1 and 2 the numeral IB designates a driving chain which runs over sprockets (not shown) at the front and rear of the stoker, the

chains being located near the side edges of the grate or at intervening points also. The chains are provided with rollers Il running on a rail, a portion of the latter appearing at i2 in Fig. 2. The chains drive a plurality of transversely extending carrier bars I3 which are formed with a number of air slots I4 located between dovetail portions engaging corresponding dovetail slots on the under side of the keys 2i) which are mounted in side by side relation with the carrier bars. are shown in Fig. l. Air is admitted to the fuel bed through passages between the side faces of adjacent keys.

In accordance with the present invention each key is formed along both side faces thereof with For clarity of illustration only a few keys provided along both front and rear side edges with seal ribs 23, 24 at the front end and 25, 26 at the rear end. These seal ribs are in trans verse alignment with respect to the keys and are of the same width as the overall width of the rib portions 2| so as to form' spacing means for the keys at their ends, so that the ribportions 2i of adjacent keys are kept in alignment longitudinally of the keys. This .forms narrow throats placing the recesses 22 on the side face of one key in communication with the recesses on the side face ofy an adjacent key so as to produce a continuous zig-zag slot between the opposing faces of adjacent keys except at their ends, or where special sealing ribsl are provided as Vdescribed hereinafter.. In previous constructions fuel supporting keys have been provided on their side faces with laterally projecting spacing bosses which interrupt the continuity of the air passage formed between adjacent keys by thus spacing them. Consequently, in such keys the passage would have to be of greater Width to obtain the same free area as is afforded by the continuous zig-zag slot that characterizes keys embodying this invention. Furthermore, the offset relation of the recesses in the faces of the keys and the throats connecting them permits longin tudinal arching of the fuel between the projecting rib portions 2l on the keys and thereby materially reduces the amount of fine fuel sifting through the grate during operation.

The rib 23 on the side face of a key at its front edge terminates at its upper end short of a small rib 30 and parallels a rib 2l extending downwardly and rearwardly on the side face to form a nozzle-like air passage 32 for directing air to the space between the ends of consecutive keys. As shown in Fig. 5 the ribs 23 and 24 taper inwardly and merge into the face of the web or body portion 33 of the key so that air may enter from the wind box to supply that portion of the key extending forwardly beyond the carrier Y bar I3. Y

As mentioned above the keys are also provided with ribs 25 and 26 extending along the rear side edge from the upper rear edge 34 to the lower rear edge 35 as shown in Fig. 4. The sealing rib 25 forms part of the apparent side face of the opposed face of adjacent bars. The keys 2&1 are 55 key at the rear end but is in reality a rib projecting laterally from the narrow body or web portion 33 of the key. The sealing rib 26 on the opposite face of the bar appears better defined from a visual standpoint because it lies adjacent and partly bounds a recess 36 adapted to receive an additional sealing and interlocking rib 3l on the opposed face of the adjacent key, this rib also extending from adjacent the upper rear edge 34 to adjacent the lower rear edge 35 and projecting laterally beyond the side face of the rib 25. The keys are also provided on each side face with ribs 40 extending from the upper rear edge 34 downwardly and forwardly to the lower side edge 4I at 42 so that when the keys are mounted side by side on the carrier bars the lower end of the ribs 40 lie adjacent the rear side edges of the slots I4 in the carrier bar. 4I thus prevent air passing upwardly through the passages I4 from flowing to the space between the ends of contiguous keys and permit air to be supplied through the longitudinally zigzag air passage to the entire top edge of the keys. The ribs 25, 2B and 3l serve to prevent air flowing from the wind box upwardly between the ends of contiguous keys particularly when the keys are canted with respect to each other and thus open up a space between the rear edge of one bar and the front end edge of the next bar in passing around the sprockets, as indicated in Fig. 2.

What I claim is:

l. In a travelling grate having a carrier bar provided with a skeleton dovetail extending lengthwise thereof and formed with air slots between the dove-tail portions; a plurality of fuel supporting keys mounted in side by side relation on said dove-tail formed on their adjacent side faces with contacting ribs extending from their top rear edges to their bottom rear edges to form an air seal at the rear ends of said keys; and other contacting ribs extending along the side faces of said keys from said top rear edges thereof to the points on their lower side edges immedi- The ribs ately adjacent the rear edge of the air slot in said carrier bar for preventing air from said slot passing rearwardly.

2. In a travelling grate having a carrier bar provided with a skeleton dove-tail extending lengthwise thereof and formed with air slots between the dove-tail portions; fuel supporting keys mounted in side by side relation on said carrier bar each provided on one side face with a laterally projecting rib extending from adjacent its top rear edge to adjacent its bottom rear edge and formed on its opposite face with a similarly located recess conforming to the contour of and adapted to receive the rib on the side face of an adjacent bar.

3. In a travelling grate having carrier bars, each bar being provided with a skeleton dovetail extending lengthwise thereof and formed with air slots between the dovetail portions; a plurality of fuel supporting keys mounted on said dovetails of said bars formed on their side faces with contacting ribs extending from their top rear edges to their bottom rear edges and formed on their side faces with other contacting ribs extending along their front edges from the bottom of nozzle-like air passages just below the top of each of the keys and thence for a substantial distance downwardly, said contacting ribs along the rear edges of the keys lying in substantial contact with said contacting ribs along the front edges of the next adjacent keys, whereby the air flow to the space between the adjacent keys is admitted substantially only through said nozzlelike air passages.

WILLIAM LLOYD. 

